<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <Button android:id="@+id/downloadTxt" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="下載文本文件" /> <Button android:id="@+id/downloadMp3" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="下載MP3文件" /> </LinearLayout>
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<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.learning.example" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".Download" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> <uses-sdk android:minSdkVersion="8" /> <!-- 訪問網絡和操作SD卡 加入的兩個權限配置--> <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> </manifest>
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package com.learning.example.util; import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; public class HttpDownloader { private URL url = null; /** * 根據URL下載文件,前提是這個文件當中的內容是文本,函數的返回值就是文本當中的內容 * 1.創建一個URL對象 * 2.通過URL對象,創建一個HttpURLConnection對象 * 3.得到InputStream * 4.從InputStream當中讀取數據 * @param urlStr * @return */ public String download(String urlStr){ StringBuffer sb = new StringBuffer(); String line = null; BufferedReader buffer = null; try { url = new URL(urlStr); HttpURLConnection urlConn = (HttpURLConnection)url.openConnection(); buffer = new BufferedReader(new InputStreamReader(urlConn.getInputStream())); while( (line = buffer.readLine()) != null){ sb.append(line); } } catch (Exception e) { e.printStackTrace(); } finally{ try { buffer.close(); } catch (IOException e) { e.printStackTrace(); } } return sb.toString(); } /** * * @param urlStr * @param path * @param fileName * @return * -1:文件下載出錯 * 0:文件下載成功 * 1:文件已經存在 */ public int downFile(String urlStr, String path, String fileName){ InputStream inputStream = null; try { FileUtils fileUtils = new FileUtils(); if(fileUtils.isFileExist(path + fileName)){ return 1; } else { inputStream = getInputStreamFromURL(urlStr); File resultFile = fileUtils.write2SDFromInput(path, fileName, inputStream); if(resultFile == null){ return -1; } } } catch (Exception e) { e.printStackTrace(); return -1; } finally{ try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } return 0; } /** * 根據URL得到輸入流 * @param urlStr * @return */ public InputStream getInputStreamFromURL(String urlStr) { HttpURLConnection urlConn = null; InputStream inputStream = null; try { url = new URL(urlStr); urlConn = (HttpURLConnection)url.openConnection(); inputStream = urlConn.getInputStream(); } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return inputStream; } }
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package com.learning.example.util; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import android.os.Environment; public class FileUtils { private String SDPATH; private int FILESIZE = 4 * 1024; public String getSDPATH(){ return SDPATH; } public FileUtils(){ //得到當前外部存儲設備的目錄( /SDCARD ) SDPATH = Environment.getExternalStorageDirectory() + "/"; } /** * 在SD卡上創建文件 * @param fileName * @return * @throws IOException */ public File createSDFile(String fileName) throws IOException{ File file = new File(SDPATH + fileName); file.createNewFile(); return file; } /** * 在SD卡上創建目錄 * @param dirName * @return */ public File createSDDir(String dirName){ File dir = new File(SDPATH + dirName); dir.mkdir(); return dir; } /** * 判斷SD卡上的文件夾是否存在 * @param fileName * @return */ public boolean isFileExist(String fileName){ File file = new File(SDPATH + fileName); return file.exists(); } /** * 將一個InputStream裏面的數據寫入到SD卡中 * @param path * @param fileName * @param input * @return */ public File write2SDFromInput(String path,String fileName,InputStream input){ File file = null; OutputStream output = null; try { createSDDir(path); file = createSDFile(path + fileName); output = new FileOutputStream(file); byte[] buffer = new byte[FILESIZE]; while((input.read(buffer)) != -1){ output.write(buffer); } output.flush(); } catch (Exception e) { e.printStackTrace(); } finally{ try { output.close(); } catch (IOException e) { e.printStackTrace(); } } return file; } }
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package com.learning.example; import com.learning.example.util.HttpDownloader; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class Download extends Activity { private Button downlaodTxtButton ; private Button downlaodMP3Button ; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); downlaodTxtButton = (Button)findViewById(R.id.downloadTxt); downlaodTxtButton.setOnClickListener(new DownloadTxtListener()); downlaodMP3Button = (Button)findViewById(R.id.downloadMp3); downlaodMP3Button.setOnClickListener(new DownloadMP3Listener()); } class DownloadTxtListener implements OnClickListener{ @Override public void onClick(View v) { HttpDownloader downloader = new HttpDownloader(); String lrc = downloader.download("http://172.16.11.9:8080/test/1.lrc"); System.out.println(lrc); } } class DownloadMP3Listener implements OnClickListener{ @Override public void onClick(View v) { HttpDownloader downloader = new HttpDownloader(); int result = downloader.downFile("http://172.16.11.9:8080/test/1.mp3", "voa/", "1.map3"); System.out.println(result); } } }